The present invention relates to lighting apparatus and, in particular, to lighting apparatus for illuminating well-defined limited areas. Still more particularly, certain embodiments of this invention are related to ceiling-supported indoor lighting apparatus for illuminating specific well-defined limited areas.
A wide variety of lamps and lighting apparatus have been used for illuminating limited areas such as wall areas, table or floor areas. Targeted illumination has been used for enhancing displays in various places and for purposes of general indirect lighting involving wall washing and/or lighting of other target areas or surfaces. Prior devices for targeted illumination of limited areas include, among other things, a variety of ceiling-mounted recessed lighting devices, track lighting devices and spotlights of various kinds.
Various lighting devices of the prior art have directed light from a light source onto a well-defined limited area by adjustment of means other than the light source. Examples include the structures disclosed in U.S. Pat. Nos. 5,130,908, 5,915,823, 5,897,201 and 6,045,250, issued to Jerome H. Simon.
There are a number of problems and shortcomings in certain prior art lighting devices for illuminating limited areas. It is to overcome such problems and shortcomings and to provide an improved lighting apparatus for illuminating, specific, well-defined limited areas that this invention is directed.
Certain devices of the prior art, including the devices of the aforementioned Simon patents, have light-generating and beam-establishing structures which are large and bulky, rather than compact and efficient in the use of space. For this reason, the entire lighting apparatus tends to be larger and more bulky than is sometimes desirable, and these qualities may limit the usefulness of such devices. Compactness and efficiency in use of space are important in a number of lighting applications.
In certain lighting applications, if arc lamps are used as light sources for illuminating well-defined limited areas the characteristics of the arc itself may be carried to an unacceptable extent into the final light pattern falling on the targetxe2x80x94in what might be referred to as arc-imaging. This is an undesirable artifact. When the task is illuminating specific well-defined limited areas, it is typically very desirable that the light be of highly uniform character.
Certain devices of the prior art for illuminating well-defined limited areas tend to have unacceptable levels of light losses. In every lighting application, improved efficiency of light delivery is highly desirable.
Certain prior art devices such as the aforementioned Simon devices utilize a single light source to establish plural beams extending in different radial directions within a common plane. In devices utilizing a single light source to provide plural beams, it is highly desirable to establish such beams with minimal light losses.
Many lighting devices of the prior art used for illuminating limited areas require that the light beam direction be readjusted after replacement of the lamps in such devices. For example, if such a lighting device is illuminating a work of art hanging on a wall, the changing of the lamp often necessitates adjustment of the fixture to once again center the beam on the target. This need for redirecting lighting apparatus is time consuming and undesirable.
There is a continuing need in the field of lighting apparatus, particularly with lighting apparatus of certain types, for improvements in the ease of adjusting the apparatus to properly illuminate specific well-defined limited areas. Versatility of adjustment is highly desirable:
Many lighting devices for illuminating limited areas have significant stray-light emissionsxe2x80x94emissions reaching areas other than the intended target area. This may be aesthetically displeasing and annoying. Eliminating or substantially reducing stray light emissions around and near the intended, well-defined target area is highly desirable.
A variety of lamps have been used in such devices, including among others, incandescent quartz halogen and metal halide lamps. Various recent developments regarding directional light sources and systems have been made, including those shown and described in the following co-pending, commonly-owned patent applications of Juris Sulcs, John M. Davenport and Roger F. Buelow II, all of whom are among the inventors of the instant patent herein: Ser. No. 09/454,073, filed Dec. 2, 1999, entitled xe2x80x9cEfficient Arrangement For Coupling Light Between Light Source And Light Guidexe2x80x9d; Ser. No. 09/470,156, filed Dec. 22, 1999, entitled xe2x80x9cMethod of Making Optical Coupling Devicexe2x80x9d; and Ser. No. 09/56527, filed May 5, 2000, entitled xe2x80x9cEfficient Directional Lighting System.xe2x80x9d
Therefore, it is a primary object of the present invention to provide improved lighting apparatus for illuminating selected well-defined limited areas.
Another object of the invention is to provide an improved lighting apparatus for illuminating selected limited areas which has a light-generating and beam-establishing structure and overall structure, of compact size.
Another object of this invention is to provide an improved lighting apparatus for illuminating selected particular areas which is highly adjustable and easily usable.
Another object of this invention is to provide an improved lighting apparatus for illuminating limited areas which does not require re-targeting after replacement of lamps.
Another object of the invention to provide an improved lighting apparatus for excellent and highly efficient illumination of selected limited areas, avoiding the problem of arc-imaging.
Another object of this invention is to provide an improved beam-adjustable multi-beam lighting apparatus shielding light-generating elements from view.
Another object of this invention is to provide an improved lighting apparatus for illuminating limited areas which reduces or eliminates stray light emissions.
Still another object is of the invention is to provide a lighting apparatus for illuminating limited areas which has highly versatile adjustability.
Yet another object of the invention is to provide an improved single-light-source multi-beam lighting apparatus exhibiting high efficiency in light usage.
These and other objects of the invention will be apparent from the invention disclosure which follows.
In accordance with the present invention, a lighting apparatus for illuminating well-defined limited areas is provided for mounting on a support such as a ceiling or the like. The lighting apparatus of this invention overcomes certain problems and shortcomings of the prior art, including those noted above, and provides a unique device satisfying a number of specific lighting needs.
The lighting apparatus of the invention, which is mountable on a support, includes: (1) a support frame mountable to the support; (2) a light-generating system on the support frame and including (2a) a light source, (2b) a light-gathering/directing element extending along a longitudinal axis and having an output, the light-gathering/directing element receiving light generated by the light source and directing it to the output, (2c) a guide rod extending along the longitudinal axis and having an input end in communication with the output end of the light-gathering/directing element and guiding light therethrough to an output end, and (2d) a reflector for receiving the light exiting the guide rod and reflecting the light toward a limited target area.
In certain highly preferred embodiments, the support frame is pivotably mounted to the support such that the support frame and the light-generating system supported thereon are pivotable about an axis transverse to the longitudinal axis.
In most embodiments, a second light-generating system, with each of the above-noted elements, is included in back-to-back alignment such that light is directed to first and second target areas. Most preferably, the first and second light-generating systems extend along a common longitudinal axis in first and second opposite directions and, most preferably, receive light from the same light source.
In preferred embodiments, each light-generating system also includes a first optical lens disposed between the output end of the guide rod and the reflector for modifying the light passing therethrough.
In preferred embodiments, the guide rod is formed from a thermally absorptive material so as to thermally isolate the first optical lens from the light source. Most preferably the guide rods are solid quartz rods. Each guide rod preferably has ultraviolet and infrared light-reflecting coating such that the input end of the guide rod reflects ultraviolet and infrared light generated by the light source and discourages the passing of the ultraviolet and infrared light through the guide rod.
In highly preferred embodiments include a shield interconnected to the support frame and having an opening therein, the reflector or reflectors (mirrors) reflecting light through an opening or openings in the shield to the target areas. Such shield preferably serves to prevent stray light emissions from exiting the structure.
In highly preferred embodiments, each reflector is pivotably mounted to the support frame thereby to allow the mirror(s) to be manipulated to orientations wherein the reflected light is directed to the target area(s). Preferably, such pivotable mounting is by ball-and-socket joints which connect the reflecting mirror to the support frame. Gimbal-mounting arrangements are equivalent.
In highly preferred embodiments the light-gathering/directing elements are compound parabolic collectors.
In certain preferred embodiments, the light-generating system further includes a first optical lens disposed between the output end of the guide rod and the reflector for modifying the light passing therethrough. A second optical lens may be disposed between the first optical lens and the reflector for further modifying the light passing therethrough.
It is preferable that the guide rod be a thermally absorptive material (like quartz, as mentioned above) to thermally isolate the first optical lens from the light source.